64 DOMESTICATED TROUT. 



should be tacked over this opening, so that there can 

 be no danger of anything getting in there ; and if the 

 covers do not fit down tight, they should be hooked 

 down, or caught with a spring. When the carpenter 

 puts on the covers, examine them carefully, and see 

 that there are no chinks to admit even a lizard. If 

 there are not, then your hatching boxes are complete 

 in every respect, and, if the previous suggestions have 

 been carried out, will do their work to your perfect 

 satisfaction. 



Use of Glass Grilles. 



I have proceeded thus far on the supposition that 

 troughs of carbonized wood or other material are 

 used. For the guidance of those who prefer glass 

 grilles I quote the following remarks upon them from 

 "Harper's Magazine"* and from Dr. Slack's Cata- 

 logue of fish culturist's apparatus. 



" The Coste Hatching Tray (glass grilles) consists of a 

 trough (made of earthen-ware, glass, or slate) about two 

 feet long, six inches wide, and four inches deep. On the 

 inside, about two and a half inches from the bottom, are 

 small projections, upon which rests a glass grille, a species 

 of gridiron formed of glass tubes placed closely together, 

 the ends being confined in a wooden rack. There is a 

 spout on one side and at the top of the box to run off the 

 surplus water ; at the bottom and below the level of the 

 grille are two other openings, usually stopped, but con- 

 venient to open in order to remove the sediment which 

 from time to time collects. In using these hatching boxes, 

 water can be supplied from a water-cooler through a filter, 



* Harper's Magazine, November, 1868, pp. 728, 729. 



